Meniscus tears accelerate joint space loss and lateral meniscal extrusion increases risk of knee arthroplasty in middle‐aged adults

Abstract

We sought to use publicly available data from the Osteoarthritis Initiative (OAI), a multicenter prospective cohort study, to determine the rate of joint space loss and likelihood of knee arthroplasty due to MRI‐diagnosed meniscal tears or meniscal extrusion in middle‐aged adults with no to mild knee osteoarthritis. Participants (n=2199; mean age 60.2 years) with Kellgren‐Lawrence osteoarthritis grades 2 (mild) (48.7%) or 0‐1 (none) (51.3%) underwent knee MRIs at enrollment and were followed radiographically for 8 years and for TKA for 9 years. Rate of joint space loss and risk of arthroplasty due to meniscal tears and/or extrusion were determined by multivariate modeling. Prevalence of baseline medial meniscus tears was 21.3% and lateral tears was 12.8%; 26.9% had medial meniscal extrusion (79.6% <2 mm, 20.4% 2+ mm) and 5.4% had lateral extrusion (75.9% <2 mm, 24.1% 2+ mm). Median medial joint space loss was 0.06 mm/year and lateral was 0.05 mm/year. Medial tears regardless of extrusion were associated with accelerated medial joint space loss (additional mean 0.05 mm/year; p=0.001). Lateral tears were associated with accelerated lateral joint space loss (additional 0.09 mm/year; p<0.001) as was lateral extrusion (additional 0.10 mm/year; p<0.001). The yearly incidence of knee arthroplasty was 0.5% without lateral extrusion, 1.5% with extrusion <2.0 mm, and 3.7% with extrusion ≥2.0 mm. Both medial and lateral tears accelerate joint space loss in middle age adults. Lateral meniscal extrusion further accelerates joint space loss and increases risk of progression to total knee arthroplasty within 9 years.